Priming composition



Patented Dec. 22, 1953 Remington Arms Company, Inc., Bridgeport,

Conn., a corporation of Delaware No Drawing. Application August 24,1950, Serial No. 181,325

3 Claims.

This invention relates to a novel composition of matter which is adouble salt of styphnic and hypophosphoric acids. For convenience, itwill be called Potassium Cupric Styphnate-Cupric Hypophosphite. It isexplosive in character, and particularly adapted to use as a. combustioninitiator for ammunition priming and other deflagrating compositions.

The novel salt may be prepared as follows:

To a suspension of about grams of styphnic acid in 100 cc. of water, ata temperature between about 40 C. and about 60 C., and under agitation,there is added about 10 cc. of S-normal potassium hydroxide solution and10 grams of sodium hypophosphite. After about ten minutes of continuousstirring, there is added a solution of about grams of copper sulphate in50 cc. of water, this addition being dropwise and extending over aperiod of about twenty minutes. A precipitate of long, narrow pale greencrystalline plates is formed. This precipitate, which has an apparentdensity of 0.28 gram/cc, contains 7.64% to 7.85% potassium, 7.19% to7.20% phosphorous, and 14.7% copper, thus approaching the theoreticalanalysis of a complex salt of the formula:

The differences between analysis and theoretical composition may well bedue to the impurity of the commercial styphnic acid used, the difficultyof analysis for potassium, and/or the presence of some acid cupricstyphnate-cupric hypophosphite.

The new compound is not ultra-sensitive to static electricity, requiringthe discharge of a 300 mmf. capacitor at 1,000 volts for certain firing.On a temperature gradient bar it explodes instantly at a temperature of150 C. It is particularly useful as a combustion initiator in ammunitionpriming compositions, in which it replaces such combustion initiators aslead styphnate with highly desirable results. In a standard drop test. apriming composition utilizing Potassium Cupric Styphnate-CupricHypophosphite shows an average sensitivity of 5.74", and a standarddeviation of 1.5. A counterpart mixture containing lead styphnate has anaverage sensitivity of 5.58", and a standard deviation of 1.6". Loadedcartridges primed with a mixture containing the novel salt show anaverage barrel time of 1.97 milliseconds with a standard deviation of0.047 millisecond; while corresponding cartridges primed with a leadstyphnate mixture have an average barrel time of 2.08 millisecondsRange, percent Preferred, percent Potassium copper styphnate copperhypophosphite Tetrazene. Barium nitrate. 1 Glass Sensitizers other thantetrazene may be used, it being understood that a sensitizer is asubstance which explosively decomposes under friction or percussion withthe generation of heat or flame. oxidizers other than barium nitrate andfrictionators other than glass may also be used, butpreferably allingredients are so chosen that none of them contain either combined orfree lead, or salts such as chlorates which yield toxic. corrosive orhygroscopic reaction products or residues. Corrosive and hygroscopicresidues such as potassium chloride are very destructive to gun barrelsif not promptly and completely removed. Toxic residues such as free orcombined lead are undesirable and, in intensively used indoor ranges,may become hazardous. It will be noted that the priming composition ofthis invention is entirely free from toxic residue pro ducing lead ormercury compounds, and is also free from corrosion producing potassiumsalts and chlorates.

The use of priming compositions of this type enables the production ofcartridges the firing residues of which are entirely free of toxicingredients. The firing of cartridges which contain lead, either free oras a compound, inevitably produces a smoke or other residue containingtoxic lead. For indoor shooting the production of such residues poses aserious problem, since, in the absence of very abundant ventilation,toxic residues may accumulate in the atmosphere to a concentration whichis hazardous to the occupants. It will be noted that the above primingcompositionsdo not contain any lead compounds, and the use ofcompositions of this character with leadless projectiles such as theprojectiles nate-Copper Hypophosphite 35% to 40%, tetra-V 4 zene 2% to5%, barium nitrate 20% to 40%, and glass 20% to 40%.

3. An ammunition priming composition consisting essentially of PotassiumCopper Styphnate-Copper Hypophosphite 38%, tetrazene 4%, barium nitrate25%, glass 33 JOSEPH F. KENNEY.

No references cited.

1. THE COMPOSITION OF MATTER POTASSIUM CUPIC STYPHNATE-CUPRICHYPOPHOSPHITE.
 2. AN AMMUNITION PRIMING COMPOSITION CONSISTINGESSENTIALLY OF POTASSIUM COPPER STYPHNATE-COPPER HYPOPHOSPHITE 35% TO40%, TETRAZENE 2% TO 5%, BARIUM NITRATE 20% TO 40%, AND GLASS 20% TO40%.